CRYSTAL-STRUCTURES OF HYDRATED (20-DEGREES-C) AND DEHYDRATED (250-DEGREES-C) FORMS OF ZEOLITE CDX

The crystal structures of zeolite CdX obtained from zeolite NaX by ion exchange are determined for the same sample in the hydrated [Fd3, a = 24.858(8) Angstrom, 895 F(hkl), and R = 0.046] and dehydrated [250 de grees C, Fd3, a = 25.04(1) Angstrom, 723 F(hkl), and R = 0.047] forms. It is shown that removing the water molecules from the coordination p olyhedra of cadmium cations results in the migration of these cations to the positions with a more complete oxygen coordination. In turn, th is redistribution of cations leads to geometric changes in the alumino silicate framework.